Hybrid data transport for a virtualized distributed antenna system

ABSTRACT

A system for data transport in a Distributed Antenna System (DAS) includes a plurality of remote Digital Access Units (DAUs) located at a Remote location. The plurality of remote DAUs are coupled to each other and operable to transport digital signals between the plurality of remote DAUs. The system also includes a plurality of central hubs. Each of the plurality of central hubs is in communication with one of the remote DAUs using an electrical communications path. The system further includes a plurality of transmit/receive cells. Each of the plurality of transmit/receive cells includes a plurality of remote hubs. Each of the remote hubs in one of the plurality of transmit/receive cells is in communication with one of the plurality of central hubs using an optical communications path.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/604,341, filed on Feb. 28, 2012, entitled “Hybrid Data Transportfor a Virtualized Distributed Antenna System,” the disclosure of whichis hereby incorporated by reference in its entirety for all purposes.

BACKGROUND OF THE INVENTION

Wireless communication systems employing Distributed Antenna Systems(DAS) are available. A DAS typically includes one or more host units,optical fiber cable or other suitable transport infrastructure, andmultiple remote antenna units. A radio base station is often employed atthe host unit location commonly known as a base station hotel, and theDAS provides a means for distribution of the base station's downlink anduplink signals among multiple remote antenna units. The DAS architecturewith routing of signals to and from remote antenna units can be eitherfixed or reconfigurable.

A DAS is advantageous from a signal strength and throughput perspectivebecause its remote antenna units are physically close to wirelesssubscribers. The benefits of a DAS include reducing average downlinktransmit power and reducing average uplink transmit power, as well asenhancing quality of service and data throughput.

Despite the progress made in wireless communications systems, a needexists for improved methods and systems related to wirelesscommunications.

SUMMARY OF THE INVENTION

The present invention generally relates to wireless communicationsystems employing Distributed Antenna Systems (DAS) as part of adistributed wireless network. More specifically, the present inventionrelates to a DAS utilizing a software configurable radio (SCR). In aparticular embodiment, the present invention has been applied to the useof coupled remote Digital Access Units. The methods and systemsdescribed herein are applicable to a variety of communications systemsincluding systems utilizing various communications standards.

Wireless and mobile network operators face the continuing challenge ofbuilding networks that effectively manage high data-traffic growthrates. Mobility and an increased level of multimedia content for endusers typically employs end-to-end network adaptations that support newservices and the increased demand for broadband and flat-rate Internetaccess. One of the most difficult challenges faced by network operatorsis caused by the physical movement of subscribers from one location toanother, and particularly when wireless subscribers congregate in largenumbers at one location. A notable example is a business enterprisefacility during lunchtime, when a large number of wireless subscribersvisit a lunch room or cafeteria location in the building. At that time,a large number of subscribers have moved away from their offices andusual work areas. It's likely that during lunchtime, there are manylocations throughout the facility where there are very few subscribers.If the indoor wireless network resources were properly sized during thedesign process for subscriber loading as it is during normal workinghours when subscribers are in their normal work areas, it is very likelythat the lunchtime scenario will present some unexpected challenges withregard to available wireless capacity and data throughput.

According to an embodiment of the present invention, a system for datatransport in a Distributed Antenna System is provided. The systemincludes a plurality of remote DAUs located at a Remote location. Theplurality of remote DAUs are coupled to each other and operable totransport signals between the plurality of remote DAUs. The system alsoincludes a plurality of central hubs. Each of the plurality of centralhubs are in communication with one of the remote DAUs using anelectrical communications path. The system further includes a pluralityof transmit/receive cells. Each of the plurality of transmit/receivecells includes a plurality of remote hubs. Each of the remote hubs inone of the plurality of transmit/receive cells is in communication withone of the plurality of central hubs using an optical communicationspath (e.g., an optical fiber, which is also referred to as an opticalcable and is operable to support both digital and analog signals (i.e.,RF over fiber)).

According to another embodiment of the present invention, a system fordata transport in a Distributed Antenna System is provided. The systemincludes a plurality of remote DAUs located at a Remote location. Theplurality of remote DAUs are coupled to each other and operable totransport signals between the plurality of remote DAUs. The system alsoincludes a central hub in communication with each of the remote DAUsusing a plurality of electrical communications paths (e.g., an RF cablesuitable for transporting analog signals) and a plurality oftransmit/receive cells. Each of the plurality of transmit/receive cellsincludes a plurality of remote hubs. Each of the remote hubs is incommunication with the central hub using one or more opticalcommunications paths.

According to an embodiment of the present invention, a system forrouting signals in a Distributed Antenna System (DAS) is provided. Thesystem includes a plurality of Base Transceiver Stations (BTS), eachhaving one or more sectors and a plurality of BTS RF connections, eachbeing coupled to one of the one or more sectors. The system alsoincludes a plurality of local Digital Access Units (DAUs) located at aLocal location. Each of the plurality of local DAUs is coupled to eachother, operable to route signals between the plurality of local DAUs,and coupled to at least one of the plurality of BTS RF connections. Thesystem further includes a plurality of remote DAUs located at a Remotelocation. The plurality of remote DAUs are coupled to each other andoperable to transport signals between the plurality of remote DAUs. Theplurality of local DAUs can be coupled via at least one of Ethernetcable, Optical Fiber, Microwave Line of Sight Link, Wireless Link, orSatellite Link.

The plurality of local DAUs can be connected to the plurality of remoteDRUs via at least one DWDM and at least one optical fiber. The pluralityof remote DAUs can be coupled via at least one of Ethernet cable,Optical Fiber, Microwave Line of Sight Link, Wireless Link, or SatelliteLink. In an embodiment, the plurality of remote DAUs include one or moreOptical interfaces or one or more RF interfaces. In another embodiment,the plurality of remote DAUs include one or more Optical interfaces. Asan example, the one or more Optical interfaces can include an opticalinput and an optical output. In some embodiments, the system alsoincludes a server coupled to each of the plurality of remote DAUs. Asingle DAU port is connected to a plurality of BTSs in someimplementations.

According to another embodiment of the present invention, a system forrouting signals in a DAS is provided. The system includes a plurality oflocal Digital Access Units (DAUs) located at a Local location. Theplurality of local DAUs are coupled to each other and operable to routesignals between the plurality of local DAUs. The system also includes aplurality of remote Digital Access Units (DAUs) located at a Remotelocation coupled to each other and operable to transport signals betweenthe remote DAUs and each other and a plurality of Base TransceiverStations (BTS). The system further includes a plurality of BaseTransceiver Station sector RF connections coupled to the plurality oflocal DAUs and operable to route signals between the plurality of localDAUs and the plurality of Base Transceiver Stations sector RFconnections and a plurality of DRUs connected to a plurality of remoteDAUs via at least one of a Ethernet cable, Optical Fiber, RF Cable,Microwave Line of Sight Link, Wireless Link, or Satellite Link.

According to an alternative embodiment of the present invention, asystem for routing signals in a DAS is provided. The system includes afirst BTS having a plurality of sectors and a second BTS having aplurality of sectors. Each of the plurality of sectors of the first BTSincludes an RF port operable to receive an RF cable. Each of theplurality of sectors of the second BTS includes an RF port operable toreceive an RF cable. The system also includes a first local DAU locatedat a Local location. The first local DAU is connected to an RF port of afirst sector of the first BTS through an RF cable and an RF port of afirst sector of the second BTS through an RF cable. The system furtherincludes a second local DAU located at a Local location. The secondlocal DAU is connected to an RF port of a second sector of the first BTSthrough an RF cable and an RF port of the second sector of the secondBTS through an RF cable. Additionally, the system includes acommunications media connecting the first local DAU and the second localDAU, a mux/demux coupled to the first local DAU and the second localDAU, a network connection between the mux/demux and a second mux/demux,and a plurality of remote DAUs located at a Remote location andconnected to the second mux/demux. The plurality of remote DAUs arecoupled to each other and to a server.

The plurality of local DAUs can be connected to the plurality of remoteDRUs via at least one DWDM and at least one optical fiber. In someimplementations, the plurality of remote DAUs are coupled via at leastone of Ethernet cable, Optical Fiber, Microwave Line of Sight Link,Wireless Link, or Satellite Link. The plurality of remote DAUs caninclude one or more Optical interfaces or one or more RF interfaces. Theone or more Optical interfaces can include an optical input and anoptical output. In a specific embodiment, the system also includes aserver coupled to each of the plurality of remote DAUs. In anembodiment, a single DAU port is connected to a plurality of BTSs.

Numerous benefits are achieved by way of the present invention overconventional techniques. For instance, embodiments of the presentinvention can virtually transport the hotel base stations to a remotelocation, which may be a considerable distance from the physicallocation (e.g., kilometers of separation). Additionally, embodimentsenable the routing capacity at the remote location. These and otherembodiments of the invention along with many of its advantages andfeatures are described in more detail in conjunction with the text belowand attached figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram according to one embodiment of the inventionshowing the basic structure and an example of the transport routingbased on having multiple 3 sector BTSs with 3 Digital Access Units(DAUs) at a Local Location, 3 DAUs at a Remote Location and RFinterfaces at the Remotes. In this embodiment, three sector BTSs areconnected to a daisy chained group of DAUs at both the local and remotelocations.

FIG. 2 is a block diagram according to one embodiment of the inventionshowing the basic structure and an example of the transport routingbased on having multiple 3 sector BTSs with 3 DAUs at a Local Location,3 DAUs at a Remote Location and Optical interfaces at the Remotes.

FIG. 3 is a block diagram according to one embodiment of the inventionshowing the basic structure and an example of the transport routingbased on having multiple 3 sector BTSs with 3 DAUs at a Local Location,3 Digital Remote Units (DRUB) at a Remote Location and Opticalinterfaces at the Remotes.

FIG. 4 is a block diagram illustrating a DAU, which contains physicalNodes and a Local Router, according to an embodiment of the presentinvention.

FIG. 5 is a block diagram illustrating a DRU according to an embodimentof the present invention.

FIG. 6 is a block diagram according to one embodiment of the inventionshowing the basic structure and an example of the transport routingbased on having multiple 3 sector BTSs with 3 DAUs at a Local Location,3 DAUs at a Remote Location interfacing to multiple Central Hubs.

FIG. 7 is a block diagram according to one embodiment of the inventionshowing the basic structure and an example of the transport routingbased on having multiple 3 sector BTSs with 3 DAUs at a Local Location,3 DAUs at a Remote Location interfacing to one Central Hub.

FIG. 8 is a block diagram of a Central Hub according to an embodiment ofthe present invention.

FIG. 9 is a block diagram of a Remote Hub according to an embodiment ofthe present invention.

FIG. 10 is block diagram of a Central Hub suitable for dynamicsectorization according to an embodiment of the present invention.

FIG. 11 is a simplified flowchart illustrating a method of transportingsignals according to an embodiment of the present invention.

FIG. 12 is a simplified flowchart illustrating a method of performingdynamic sectorization according to an embodiment of the presentinvention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

To accommodate variations in wireless subscriber loading at wirelessnetwork antenna locations at various times of day and for different daysof the week, there are several candidate conventional approaches.

One approach is to deploy many low-power high-capacity base stationsthroughout the facility. The quantity of base stations is determinedbased on the coverage of each base station and the total space to becovered. Each of these base stations is provisioned with enough radioresources, i.e., capacity and broadband data throughput to accommodatethe maximum subscriber loading which occurs during the course of theworkday and work week. Although this approach typically yields a highquality of service for wireless subscribers, the notable disadvantage ofthis approach is that many of the base stations' capacity is beingwasted for a large part of the time. Since a typical indoor wirelessnetwork deployment involves capital and operational costs which areassessed on a per-subscriber basis for each base station, the typicallyhigh total life cycle cost for a given enterprise facility is far fromoptimal.

A second candidate approach involves deployment of a DAS along with acentralized group of base stations dedicated to the DAS. A conventionalDAS deployment falls into one of two categories. The first type of DASis “fixed”, where the system configuration doesn't change based on timeof day or other information about usage. The remote units associatedwith the DAS are set up during the design process so that a particularblock of base station radio resources is thought to be enough to serveeach small group of DAS remote units. A notable disadvantage of thisapproach is that most enterprises seem to undergo frequentre-arrangements and re-organizations of various staff groups within theenterprise. Therefore, it's highly likely that the initial DAS setupwill need to be changed from time to time, requiring deployment ofadditional direct staff and contract resources with appropriate levelsof expertise regarding wireless networks.

The second type of DAS is equipped with a type of network switch whichallows the location and quantity of DAS remote units associated with anyparticular centralized base station to be changed manually. Althoughthis approach would appear to support dynamic DAS reconfiguration basedon the needs of the enterprise or based on time of day, it frequentlyimplies that additional staff resources would need to be assigned toprovide real-time management of the network. Another issue is that it'snot always correct or best to make the same DAS remote unitconfiguration changes back and forth on each day of the week at the sametimes of day. Frequently it is difficult or impractical for anenterprise IT manager to monitor the subscriber loading on each basestation. And it is almost certain that the enterprise IT manager has nopractical way to determine the loading at a given time of day for eachDAS remote unit; they can only guess the percentage loading.

Another major limitation of conventional DAS deployments is related totheir installation, commissioning and optimization process. Somechallenging issues which must be overcome include selecting remote unitantenna locations to ensure proper coverage while minimizing downlinkinterference from outdoor macro cell sites, minimizing uplinkinterference to outdoor macro cell sites, and ensuring properintra-system handovers while indoors and while moving from outdoors toindoors (and vice-versa). The process of performing such deploymentoptimization is frequently characterized as trial-and-error. Therefore,the results may not be consistent with a high quality of service.

According to embodiments of the present invention, a highly efficient,easily deployed and dynamically reconfigurable wireless network isprovided. The advanced system architecture provided by embodiments ofthe present invention provides a high degree of flexibility to manage,control, enhance and facilitate radio resource efficiency, usage andoverall performance of the distributed wireless network. This advancedsystem architecture enables specialized applications and enhancementsincluding, but not limited to, flexible simulcast, automatic trafficload-balancing, network and radio resource optimization, networkcalibration, autonomous/assisted commissioning, carrier pooling,automatic frequency selection, radio frequency carrier placement,traffic monitoring, and/or traffic tagging. Embodiments of the presentinvention can also serve multiple operators, multi-mode radios(modulation-independent) and multiple frequency bands per operator toincrease the efficiency and traffic capacity of the operators' wirelessnetworks.

Accordingly, embodiments of the DAS network provide a capability forFlexible Simulcast. With Flexible Simulcast, the amount of radioresources (such as RF carriers, LTE Resource Blocks, CDMA codes or TDMAtime slots) assigned to a particular DRU or group of DRUs can be set viasoftware control to meet desired capacity and throughput objectives orwireless subscriber needs. Applications of the present invention aresuitable to be employed with distributed base stations, distributedantenna systems, distributed repeaters, mobile equipment and wirelessterminals, portable wireless devices, and other wireless communicationsystems such as microwave and satellite communications.

A distributed antenna system (DAS) provides an efficient means ofutilization of base station resources. The base station or base stationsassociated with a DAS can be located in a central location and/orfacility commonly known as a base station hotel. The DAS networkcomprises one or more digital access units (DAUs) that function as theinterface between the base stations and the digital remote units (DRUs).The DAUs can be collocated with the base stations. The DRUs can be daisychained together and/or placed in a star configuration and providecoverage for a given geographical area. The DRUs are typically connectedwith the DAUs by employing a high-speed optical fiber link. Thisapproach facilitates transport of the RF signals from the base stationsto a remote location or area served by the DRUs. A typical base stationcomprises 3 independent radio resources, commonly known as sectors.These 3 sectors are typically used to cover 3 separate geographicalareas without creating co-channel interference between users in the 3distinct sectors. In other embodiments, additional sectors areassociated with each BTS, for example, up to or more than 12 sectors.

An embodiment shown in FIG. 1 illustrates a DAS network architectureaccording to an embodiment of the present invention and provides anexample of a data transport scenario between multiple 3 sector BaseStations and multiple remotely located DAUs. BTSs 1 through N areconnected to DAU1, DAU2, and DAU3 (i.e., local DAUs) by an RF cable inthe illustrated embodiment. Each of the local DAUs are connected toserver 130. A Coarse Wavelength Division Multiplexer/Demux (CWDM) isutilized to facilitate data transport over a single fiber 112 from thelocal location to the remote location. Another embodiment of the datatransport system could use a Dense Wavelength Division Multiplexer(DWDM). In this embodiment, the DAUs at the Local and Remote locationsare daisy chained together using optical cable 140 and 141 to achieverouting of the RF signals. Utilizing these or other suitable wavelengthdivision multiplexing techniques, each of the DAUs is able to operate ina different wavelength band. Additional description related to DAS isprovided in U.S. patent application Ser. No. 13,754,702, filed on Jan.30, 2013, entitled “Data Transport in a Virtualized Distributed AntennaSystem,” the disclosure of which is hereby incorporated by reference inits entirety for all purposes.

FIG. 1 depicts a DAS system employing multiple Digital Access Units(DAUs) at the Local location and multiple Digital Access Units (DAUs) atthe Remote location. In accordance with the present invention, each DAUprovides unique information associated with each DAU, which uniquelyidentifies data received and transmitted by a particular Digital AccessUnit. As illustrated in FIG. 1, the 3 sector base stations are connectedto a daisy chained DAS network, although other configurations areincluded within the scope of the present invention.

One feature of embodiments of the present invention is the ability toroute Base Station radio resources among the DAUs or group(s) of DAUs.In order to route radio resources available from one or more BaseStations, it is desirable to configure the individual router tables ofthe DAUs in the DAS network. This functionality is provided byembodiments of the present invention.

The DAUs are networked together to facilitate the routing of signalsamong multiple DAUs. The DAUs support the transport of the RF downlinkand RF uplink signals between the Base Station and the various DAUs.This architecture enables the various Base Station signals to betransported simultaneously to and from multiple DAUs. PEER ports areused for interconnecting DAUs.

The DAUs have the capability to control the gain (in small incrementsover a wide range) of the downlink and uplink signals that aretransported between the DAU and the base station (or base stations)connected to that DAU. This capability provides flexibility tosimultaneously control the uplink and downlink connectivity of the pathbetween a particular Remote DAU (or a group of DAUs) and a particularbase station sector.

A single optical fiber can be used for the transportation of databetween the Local DAUs and the Remote DAUs by using a Coarse WavelengthDivision Multiplexer (CWDM) and De-multiplexer, connected, for example,through optical cable 112. Embodiments of the present invention are notlimited to the use of an optical cable 112 and other communicationsmedia can be employed including Ethernet cable, Microwave Line of SightLink, Wireless Link, Satellite Link, or the like.

Referring to FIG. 1, optical fiber 112 connects the local CWDM Mux/Demuxto the Remote CWDM Mux/Demux. In the illustrated embodiment, threeoutputs are provided by the Remote CWDM Mux/Demux, for example, threedifferent optical wavelengths. The optical cables 113 connect the RemoteCWDM Mux/Demux to the remote DAUs (DAU 4, DAU 5, and DAU 6). Thus,embodiments of the present invention provide for Local DAUs (that can beconnected to each other in the illustrated daisy chain or otherconfiguration) that are connected to Remote DAUs, which can also beconnecting to each other in a daisy chain or other configuration. Asshown in FIG. 1, cables 140/141 and 142/143, which connect the Local andRemote DAUs, respectively, can be Ethernet cable, Optical cable,Microwave Line of Sight Link, Wireless Link, Satellite Link, or thelike. Additionally, although the connections between the BTSs and thelocal DAUs are illustrated as RF cables, this is not required byembodiments of the present invention and other communications media canbe utilized. Moreover, although the remote DAUs include an optical cableconnection to the remote CWDM Mux/Demux and an RF cable in the RemotePlane, the connections in the Remote plane (e.g., to mobile accessequipment) can be made using other communications media.

As illustrated in FIG. 1 at the Remote location, RF outputs are providedby the DAUs in the remote plane. In the illustrated embodiment, the DAUsare interconnected at the remote location (e.g., the DAUs are daisychained at the remote location).

Embodiments of the present invention provide methods and systems thatenable capacity shifting. As an example, a signal can be routed fromBTS1, sector 1 (121), through an RF cable to DAU1 (102), transportedover the optical fiber 111 through the Local CWDM Mux/Demux, overoptical cable 112 to the Remote CWDM Mux/Demux, through optical cable113 to DAU4 (105), and then routed down to DAU5 (106) via cable 142 andthen output through the RF cable connected to DAU5. Thus, usingembodiments of the present invention, it is possible to control thetransmission of the signal at the remote location from any of the BTSsectors (e.g., BTS1, sector 1). As illustrated, embodiments of thepresent invention provide the flexibility to route signals from apredetermined RF input cable connected to the Local DAUs to apredetermined RF output cable connected to the Remote DAUs.Additionally, in the reverse direction, signals can be routed from apredetermined RF input cable connected to the Remote DAUs to apredetermined RF output cable connected to the Local DAUs. As anexample, a signal could be received on the RF cable connected to DAU5(106), routed to DAU4 (105), and then through the network. Thus,embodiments of the present invention provide the flexibility at theremote location to move capacity from one device to another, forexample, if the remote DAUs are not physically in the same location,(e.g., DAU4 (105) is in one building, DAU5 (106) is located in anotherbuilding, and DAU6 (107) is located in yet another building). In thatcase, flexibility is provided to be able to route signals in bothdirections onto different optical cables.

Referring to FIG. 1, embodiments of the present invention provide for avirtual extension or replication of the RF cables in the Hotel Plane tothe RF cables in the Remote Plane. Thus, the BTSs have been virtuallytransported from the base station hotel to the remote location since theoutput of the RF cables in the Remote Plane can be identical to theinputs to the RF cables in the Hotel Plane, enabling interface withmobile access equipment. Although the connections in the Hotel Plane areillustrated as RF cables, this is not required by embodiments of thepresent invention and other communications media are included within thescope of the present invention, including Ethernet cable, Optical Fiber,Microwave Line of Sight Link, Wireless Link, or Satellite Link. In someembodiments, summing is utilized to provide a system in which a singleDAU port is connected to a plurality of BTSs. For example, BTS 1, sector1 (120), and BTS N, sector 1 (121) could be summed and then connected toa single port in DAU 1 (102).

According to embodiments of the present invention, DAUs are utilized atboth the Local and Remote locations. The DAU communicates with a NetworkOperational Control (NOC). The NOC sends commands and receivesinformation from the DAS network. The DAS network can include aplurality of DAUs and DRUs. The DAU communicates with the network ofDRUs and the DAU sends commands and receives information from the DRUs.The DAUs include physical nodes that accept and deliver RF signals andoptical nodes that transport data. A DAU can include an internal serveror an external server. The server is used to archive information in adatabase, store the DAS network configuration information, and performvarious traffic related processing. The server can be used tocommunicate information from the DAS Network to the NOC.

Additionally, the DRU communicates with the DAU. In some embodiments,the DRU does not communicate with the NOC. The DRU receives commandsfrom the DAU and delivers information to the DAU. The DRUs includephysical nodes that accept and deliver RF signals and optical nodes thattransport data. As illustrated in FIG. 1, the use and connection of theDAUs to each other in the Remote location provide benefits not availablein systems in which DRUs are utilized in the Remote location, forexample, the use of server 131 in connection with the remote DAUs, sincein some implementations, a server is not used with remote DRUs. In otherimplementations, the remote DRUs can be coupling to each other and canbe connected to a server as discussed in relation to FIG. 3. As shown inFIG. 1, the remote DAUs are connected through cables 142 and 143.

FIG. 1 illustrates a scenario in which signals from Sector 1 121 of BTS1 and signals from Sector 1 120 of BTS N are combined in DAU 1 102 andreplicated at the output of DAU 4 105. These combined signals may besupported and broadcast to an antenna by the single RF Cable illustratedat the output of DAU 4 105. Alternatively, the six RF cables illustratedin the hotel plane as being received at DAU 1, DAU 2, and DAU 3 can alsobe provided in the remote plane as outputs of the set of remote DAUs.Thus, embodiments in which the number of RF cables in the hotel planeand the remote plane are equal or differ are included within the scopeof the present invention.

As shown in FIG. 2, the individual base station sector's radio resourcesare transported to a daisy-chained network of DRUs. Each individualsector's radio resources provide coverage to an independent geographicalarea via the networked DRUs. FIG. 2 demonstrates how three cells, eachcell comprising an independent network of 7 DRUs, provide coverage to agiven geographical area. A server is utilized to control the switchingfunction provided in the DAS network. Referring to FIG. 2 and by way ofexample, DAU 1 (205) receives downlink signals and transmits uplinksignals from and to BTS Sector 1 (120). DAU 1 translates the RF signalsto optical signals for the downlink and translates the optical signalsto RF signals for the uplink. The optical fiber cable (215) transportsthe desired signals to and from CWDM (221) whereby the distinct DAUoptical wavelengths are multiplexed and de-multiplexed. Optical cable(214) transports all the optical signals between CWDM (221) and CWDM(220). DAU 4 (202) transports the optical signal to and from CWDM (220).DAU 4 (202) transports the uplink and downlink data to and from a daisychain of DRUs. The other DRUs in the daisy chain are involved in passingthe optical signals onward to DRU 1 (247). Although not illustrated inFIG. 2, it will be appreciated that RF cables 270 connect to the BTSs.

The signals from DAU 4 202, DAU 5 203, and DAU 6 204 are transported tothe daisy chained DRUs using optical cables 211, 212, and 213,respectively. Thus, as an alternative system to that illustrated in FIG.1, rather than replicating the RF signals provided to DAU 1, DAU 2, andDAU 3 (see RF Cables 270), the output of the remote DAUs is transportedusing the optical cables to the DRUs for broadcast.

FIG. 3 depicts a DAS system employing multiple Digital Access Units(DAUs) at the Local location and multiple Digital Remote Units (DRUs) atthe Remote location. In accordance with the present invention, each DRUprovides unique information associated with each DRU, which uniquelyidentifies data received and transmitted by a particular Digital RemoteUnit.

DRU 24 (302) is located at the Remote location, and is connected viadaisy-chain to 7 additional DRU units that occupy Cell 1 (350).Similarly, DRU 25 (303) connects to a daisy chain of DRUs occupying Cell3 and DRU 26 (304) connects to a daisy-chain of DRUs occupying Cell 2.The remote DRUs 24, 25 and 26 are interconnected which facilitates therouting of signals between DRUs.

The servers illustrated herein, for example, server 330 provide uniquefunctionality in the systems described herein. The following discussionrelated to server 330 may also be applicable to other servers discussedherein an illustrated in the figures. Server 330 can be used to set upthe switching matrices to allow the routing of signals between theremote DRUs. The server 330 can also store configuration information,for example, if the system gets powered down or one DRU goes off-lineand then you power up the system, it will typically need to bereconfigured. The server 330 can store the information used inreconfiguring the system and/or the DRUs.

FIG. 4 shows the two elements in a DAU, the Physical Nodes (400) and theLocal Router (401). The Physical Nodes translate the RF signals tobaseband for the Downlink and from baseband to RF for the Uplink. TheLocal Router directs the traffic between the various LAN Ports, PEERPorts and the External Ports. The physical nodes connect to the BTS atradio frequencies (RF). The physical nodes can be used for differentoperators, different frequency bands, different channels, or the like.The physical nodes can combine the downlink and uplink signals via aduplexer or they can keep them separate, as would be the case for asimplex configuration.

FIG. 4 shows an embodiment whereby the physical nodes have separateoutputs for the uplinks (405) and separate inputs for the downlink paths(404). The physical node translates the signals from RF to baseband forthe downlink path and from baseband to RF for the uplink path. Thephysical nodes are connected to a Local Router via external ports(409,410)). The router directs the uplink data stream from the LAN andPEER ports to the selected External U ports. Similarly, the routerdirects the downlink data stream from the External D ports to theselected LAN and PEER ports.

In one embodiment, the LAN and PEER ports are connected via an opticalfiber to a network of DAUs and DRUs. The network connection can also usecopper interconnections such as CAT 5 or 6 cabling, or other suitableinterconnection equipment. The DAU is also connected to the internetnetwork using IP (406). An Ethernet connection (408) is also used tocommunicate between the Host Unit and the DAU. The DRU can also connectdirectly to the Remote Operational Control center (407) via the Ethernetport.

FIG. 5 shows the two elements in a DRU, the Physical Nodes (501) and theRemote Router (500). The DRU includes both a Remote Router and PhysicalNodes. The Remote Router directs the traffic between the LAN ports,External Ports and PEER Ports. The physical nodes connect to the BTS atradio frequencies (RF). The physical nodes can be used for differentoperators, different frequency bands, different channels, etc. FIG. 5shows an embodiment whereby the physical nodes have separate inputs forthe uplinks (504) and separate outputs for the downlink paths (503). Thephysical node translates the signals from RF to baseband for the uplinkpath and from baseband to RF for the downlink path. The physical nodesare connected to a Remote Router via external ports (506,507). Therouter directs the downlink data stream from the LAN and PEER ports tothe selected External D ports. Similarly, the router directs the uplinkdata stream from the External U ports to the selected LAN and PEERports. The DRU also contains a Ethernet Switch (505) so that a remotecomputer or wireless access points can connect to the internet.

In some embodiments, the DAU is connected to a host unit/server, whereasthe DRU does not connect to a host unit/server. In these embodiments,parameter changes for the DRU are received from a DAU, with the centralunit that updates and reconfigures the DRU being part of the DAU, whichcan be connected to the host unit/server. Embodiments of the presentinvention are not limited to these embodiments, which are described onlyfor explanatory purposes.

FIG. 6 depicts the connection between a plurality of DAUs at the Remotelocation (i.e., DAU 4 602, DAU 5 603, and DAU 6 604) with a plurality ofCentral Hubs (670, 671, and 672). The Central Hubs operate in the analogdomain and are suitable for receiving analog signals using theillustrated RF cables 616, 617, and 618. Accordingly, the transportationbetween the Remote DAUs and the Central Hubs is via a RF cable in theillustrated embodiment (i.e., RF cables 616, 617, and 618). In thisimplementation, the RF signals are carried over fiber from the CentralHubs to the Remote Hubs, which are daisy chained as illustrated in FIG.6. Accordingly, the interconnection between the Central Hubs and theRemote Hubs is via an optical cable (i.e., optical cables 611, 612, and613) in the illustrated embodiment. FIG. 7 depicts the connectionbetween a plurality of DAUs at the Remote location with one Central Hub.The Central Hub then transports the signal to a plurality of RemoteHubs. The remote DAUs (602, 603, and 604) receive digital signals overthe optical cables 615 connected to the CWDM Mux/Demux 620, performconversion from digital to analog, and provide analog signals using RFcables 616, 617, and 618 to the set of Central Hubs.

In order to efficiently utilize the limited base station resources, thenetwork of DRUs provides the capability of re-directing their individualuplink and downlink signals to and from any of the BTS sectors. Becausethe DRUs data traffic has unique streams, the DAU Router has themechanism to route the signal to different sectors.

Referring to FIG. 6, the output RF cables 616, 617, and 618 are providedas RF outputs in the illustrated embodiment by DAU 4 (602), DAU 5 (603),and DAU 6 (604) respectively. Accordingly, access and/or interfacefunctionality is provided by embodiments of the present invention to avariety of mobile access equipment providers. RF output cables 616, 617,and 618 connect to central hubs 670, 671, and 672. Additionaldescription related to central hubs is provided in relation to FIG. 8.Thus, embodiments of the present invention provide a virtual basestation at the remote interfaces to the central hubs, since the RFoutput cables 616, 617, and 618 can replicate the RF cables in the HotelPlane of FIG. 1. Thus, a base station is virtually transported toconnect to the central hubs illustrated in FIG. 6.

FIG. 8 is a block diagram of a Central Hub according to an embodiment ofthe present invention. Referring to FIG. 8, the Central Hub receives RFsignals on RF cables 820 and includes a set of electrical to opticalconverters 805/808. In operation, the central hub receives RF signals onRF cables 820 and effectively sums the received RF signals at combiner804 to provide an RF input to the electrical to optical converter 805.As a result, the central hub receives RF signals through RF cables 820and provides an optical output on optical fiber 810, e.g., by modulatinga laser using the electrical signal received at the electrical tooptical converter 805, the laser being a component of the electrical tooptical converter 805.

In the return path, the optical signal is received using optical fiber811 and is converted to an electrical signal using optical to electricalconverter 808, which can utilize a photodiode. The converted RF signalon the return path is transported through RF cables 821.

Referring to FIG. 8, the modulators provide increased systemsflexibility, since an IF signal could be received as an input on thetransmit path and then modulated up to an RF carrier. Demodulation canbe performed in the return path as appropriate to the received anddesired signal frequencies.

Referring once again to FIG. 6, signals on RF cables 616, 617, and 618are received at the Central Hubs 670, 671, and 672, respectively. Theoutputs of the Central Hubs are optical signals, which can betransported on optical cables 611, 612, and 613 to the various remotehubs 1-21 arranged in Cells 1-3.

FIG. 9 provides additional description related to remote hubs. At theremote hub, the optical signal is received on optical fiber 910 and isconverted using optical to electrical converter 901 (e.g., including aphotodiode) to provide an RF electrical signal. An RF power amplifier920 is used to amplify the electrical signal that is then provided to adiplexer, which filters the signal before transport on RF cable 940 toan antenna. In some embodiments, the received signal can be amplified inthe optical domain using an optical amplifier and then converted to anelectrical signal. One of ordinary skill in the art would recognize manyvariations, modifications, and alternatives.

In the return/receive path, the signal received from the antenna comesin through RF cable 940, is delivered to the diplexer, which routes thesignal to low noise amplifier 930, where the signal is amplified at RFfrequencies, and electrical to optical converter 802, which can includea diode laser, thereby providing an optical output that is transportedon optical fiber 911. The optical fiber connects to one of the centralhubs illustrated in FIG. 6. In some embodiments, the electrical tooptical conversion in the return path can be performed prior to opticalamplification.

Referring once again to FIG. 6, a single optical cable 611 isillustrated as connecting central hub 670 and the remote hubs in Cell 1(650). In other implementations, the central hubs can utilize multipleoptical cables, with multiple optical cables replacing the singleoptical cable 611 illustrated in FIG. 6. At the remote plane (i.e., theoutput of DAUs 602, 603, and 604), the RF signals from the hotel planehave been replicated, which can be provided to the Central Hub fordelivery using the illustrated RF over fiber system including the RemoteHubs. Accordingly, extension of the RF over fiber system into the remoteplane is enabled by embodiments of the present invention.

FIG. 7 illustrates an alternative embodiment in which the RF cables fromthe various DAUs 702, 703, and 704 are provided as inputs in thetransmit path to a single central hub 771, which also includes multipleoutputs in the transmit path to the remote hubs. As illustrated, CentralHub 771 receives inputs from RF cables 702, 703, and 704. The signalsfrom these inputs are transmitted to the daisy chained Remote Hubs inCells 1, 2, and 3 using optical cable 711, 712, and 713. Although singleRF cables 716, 717, and 718 are illustrated for purposes of clarity, itwill be appreciated that multiple cables, as well as multiple sets of RFcables can be used to support downlink and uplink functionality asdiscussed above.

The architecture illustrated in FIG. 7 provides the capability toperform dynamic sectorization. Referring to FIG. 1, Sector 1 (121) ofBTS 1 and Sector 1 (120) of BTS N were combined in DAU 1 and transportedon optical cable 111. Sector 2 of BTS 1 and Sector 2 of BTS N werecombined in DAU 2 and Sector 3 of BTS 1 and Sector 3 of BTS N werecombined in DAU 3. Accordingly, each DAU in the hotel plane supports adifferent sector. In the remote plane, these different sectors aresupported by each of DAUs 4, 5, and 6.

As illustrated in FIG. 7, RF cables 716, 717, and 718 from DAU 4, DAU 5,and DAU 6 support each of the different sectors (RF cable 716 associatedwith Sector 1, RF cable 717 associated with Sector 2, and RF cable 718associated with Sector 3, respectively), which are provided to theCentral Hub 771. In the Central Hub 771, processing can be performed tocontrol which Sectors are transported on optical cables 711, 712, 713,respectively. As an example, all the Sector 1 signals could be supportedon optical cables 711 and 712.

Alternatively, all the Sector 1 signals could be supported on opticalcables 711, 712, and 713. Accordingly, this architecture enables dynamicsectorization.

FIG. 8 shows the primary elements in a Central Hub for the Downlink andUplink channels. The downlink channel is comprised of: Modulators (801),a RF Combiner (804), and an Electrical to Optical Converter (805). Themodulators translate the input signals onto the appropriate RF carrierfrequencies. The combiner 804 performs the summation of the Modulatedsignals. The combined signal is the input to the optical transmitterinside the Electrical to Optical Converter (805). As an example, theelectrical to optical converter 805 includes a semiconductor laser usedto generate the optical signal for transmission over optical fiber 810.The modulated analog signals after combination are fed to the electricalto optical converter to effectively modulate the optical signal, thusthe use of the term RF over fiber since the analog RF signals outputfrom the electrical to optical converter 805 are transported overoptical fiber 810. The uplink channel is comprised of: Demodulators(804), a RF Splitter (807), and an Optical to Electrical Converter(808). The optical fiber signal (811) is input into the Optical toElectrical Converter (808), which typically includes a photodiode. Theoutput from the photodiode is sent to one or more Demodulators (804)using a Splitter (807). The Demodulators (804) translate the RF inputsignals onto the appropriate carrier frequencies before they aretransmitted over the RF cables (820). Optical fiber 810 is used to sendout the RF over fiber signal for the downlink to the remote hubs. Forthe uplink which is coming from the remote hubs back towards the basestation, the RF over fiber signals will be received using optical fiber811. Referring once again to FIG. 6, optical cable(s) 611 can representa set of cables providing downlink and uplink signals illustrated usingoptical fibers 810 and 811. Additionally, FIG. 6 illustrates multiple RFcables 616 as providing the inputs to Central Hub 670, analogous to thetwo sets of RF cables 820 and 821. Thus, it will be appreciated that themultiple RF cables 616 provide multiple inputs to the Central Hubs inboth the downlink and uplink paths. In some embodiments, the DAUprovides four RF outputs, suitable for providing the multiple RF signalscarried by RF cables 820 and receiving multiple RF cables 821. Similardiscussion applies to RF cables 617 and 618.

FIG. 9 shows the primary elements in a Remote Hub for the Downlink andUplink channels. An example of a Remote Hub as illustrated in FIG. 9 isRemote Hub (640) illustrated FIG. 6 or Remote Hub 2 (740) illustrated inFIG. 7. The downlink channel is comprised of an Optical to ElectricalConverter (901) and a Power Amplifier (920). The Optical to ElectricalConverter (901) includes a photodiode. The output of the Optical toElectrical Converter is input into a Power Amplifier (920) thatamplifies the RF signal. The uplink channel includes a Low NoiseAmplifier (930) and an Electrical to Optical Converter (902). The LowNoise Amplifier (930) amplifies the received signal from the Diplexer(950) and outputs the RF signal to the Electrical to Optical Converter(902). The Electrical to Optical Converter (902) includes an opticalTransmitter. The Diplexer (950) serves as a 3 port filter that separatesthe Downlink signals form the Uplink signals and interfaces with the RFcable that connects to the antenna.

FIG. 10 is block diagram of a Central Hub suitable for dynamicsectorization according to an embodiment of the present invention. TheCentral Hub illustrated in FIG. 10 shares some similarities with theCentral Hub illustrated in FIG. 8 and the description provided in FIG. 8is applicable to common components as appropriate. Switching matrix 1050is provided to switch

RF signals received on RF cables 1070 to differentmodulator/combiner/electrical to optical converter sets.

Referring to FIG. 10, the Central Hub includes a switching matrix 1050that is used to route the RF signals received from RF cables 1070 and1060 to the various modulators and from the various modulators1001-1003, 1021-1023, 1034-1036, and 1044-1046. One feature of theCentral Hub with the illustrated switching matrix is the ability toallocate RF signals from different BTS sectors to different opticaloutputs. This feature enables dynamic sectorization of BTS resources.Each optical output from the Central Hub (i.e., optical fibers 1010 and1011) delivers the optically modulated RF signal to a daisy chain ofRemote Hubs as illustrated in FIG. 7. Accordingly, the switching matrixhas the capability to route the BTS sectors to the various Remote Hubs.

FIG. 11 is a simplified flowchart illustrating a method of transportingsignals according to an embodiment of the present invention. The methodincludes providing a set of replicated signals in a remote plane (1110),receiving a first replicated signal at an RF input of a first centralhub (1112), and receiving a second replicated signal at an RF input of asecond central hub (1114). The replicated signals can be analog signalsand providing the set of replicated signals can include transportingthese analog signals using an RF cable. Referring to FIG. 6, RF cables616, 617, and 618, which each represent sets of RF cables, supportreplicated signals that were initially present in the Hotel plane (seeFIG. 1). In an embodiment, each set of RF cables can support signalsassociated with a sector of a set of BTSs (e.g., Sector 1 of BTS 1 andBTS 2 supported by a first set of RF cables and Sector 2 of BTS 1 andBTS 2 supported by a second set of RF cables).

The method also includes transporting a first optical signal associatedwith the first replicated signal to a first remote hub (1116) andtransporting a second optical signal associated with the secondreplicated signal to a second remote hub (1118). In the embodimentillustrated in FIG. 6, transporting the first optical signal comprisestransmitting the first optical signal though a first optical fiber 611and transporting the second optical signal comprises transmitting thesecond optical signal through a second optical fiber 612.

The method further includes broadcasting a first analog signal from thefirst remote hub (1120) and broadcasting a second analog signal from thesecond remote hub (1122). As illustrated in FIG. 6, the daisy chainedremote hubs in each of the three cells is used to broadcast analogsignals associated with the RF over fiber signals transmitted usingoptical cables 611, 612, and 613.

It should be appreciated that the specific steps illustrated in FIG. 11provide a particular method of transporting signals according to anembodiment of the present invention. Other sequences of steps may alsobe performed according to alternative embodiments. For example,alternative embodiments of the present invention may perform the stepsoutlined above in a different order. Moreover, the individual stepsillustrated in FIG. 11 may include multiple sub-steps that may beperformed in various sequences as appropriate to the individual step.Furthermore, additional steps may be added or removed depending on theparticular applications. One of ordinary skill in the art wouldrecognize many variations, modifications, and alternatives.

FIG. 12 is a simplified flowchart illustrating a method of performingdynamic sectorization according to an embodiment of the presentinvention. The method includes providing a set of replicated signals ina remote plane (1210) and receiving the set of replicated signals at RFinputs of a central hub (1212). Referring to FIG. 7, RF cables 716, 717,and 718, which each represent sets of RF cables, support replicatedsignals that were initially present in the Hotel plane (see FIG. 1). Inan embodiment, each set of RF cables can support signals associated witha sector of a set of BTSs (e.g., Sector 1 of BTS 1 and BTS 2 supportedby a first set of RF cables and Sector 2 of BTS 1 and BTS 2 supported bya second set of RF cables).

The method also includes switching a first replicated signal from afirst RF input to a second modulator (1214), switching a secondreplicated signal from a second RF input to a first modulator (1216) andmodulating the first replicated signal and the second replicated signal(1218). In an embodiment, the first replicated signal comprises a firstanalog signal associated with a first set of sectors and the secondreplicated signal comprises a second analog signal associated with asecond set of sectors. Switching is performed in the embodimentillustrated in FIG. 10 using a switching matrix of the central hub thatis coupled to the RF inputs of the central hub. Thus, embodiments of thepresent invention provide the ability to switch signals in order todirect signals associated with various sectors to different cells of thesystem.

The method further includes converting a signal associated with thefirst replicated signal to a first optical signal (1220) and convertinga signal associated with the second replicated signal to a secondoptical signal (1222). As illustrated in FIG. 10, after switching andmodulation, several signals can be combined prior to electrical tooptical conversion. Thus, the signal associated with the replicatedsignal may include several modulated and combined replicated signals. Asillustrated in FIG. 10, the switching matrix can be further coupled to aplurality of sets of modulators.

Additionally, the method includes providing the first optical signal ata first optical output of the central hub (1224) and providing thesecond optical signal at a second optical output of the central hub(1226).

It should be appreciated that the specific steps illustrated in FIG. 12provide a particular method of performing dynamic sectorizationaccording to an embodiment of the present invention. Other sequences ofsteps may also be performed according to alternative embodiments. Forexample, alternative embodiments of the present invention may performthe steps outlined above in a different order. Moreover, the individualsteps illustrated in FIG. 12 may include multiple sub-steps that may beperformed in various sequences as appropriate to the individual step.Furthermore, additional steps may be added or removed depending on theparticular applications. One of ordinary skill in the art wouldrecognize many variations, modifications, and alternatives.

It is also understood that the examples and embodiments described hereinare for illustrative purposes only and that various modifications orchanges in light thereof will be suggested to persons skilled in the artand are to be included within the spirit and purview of this applicationand scope of the appended claims.

Table 1 is a glossary of terms used herein, including acronyms.

TABLE 1 Glossary of Terms ACLR Adjacent Channel Leakage Ratio ACPRAdjacent Channel Power Ratio ADC Analog to Digital Converter AQDM AnalogQuadrature Demodulator AQM Analog Quadrature Modulator AQDMC AnalogQuadrature Demodulator Corrector AQMC Analog Quadrature ModulatorCorrector BPF Bandpass Filter CDMA Code Division Multiple Access CFRCrest Factor Reduction DAC Digital to Analog Converter DET DetectorDHMPA Digital Hybrid Mode Power Amplifier DDC Digital Down Converter DNCDown Converter DPA Doherty Power Amplifier DQDM Digital QuadratureDemodulator DQM Digital Quadrature Modulator DSP Digital SignalProcessing DUC Digital Up Converter EER Envelope Elimination andRestoration EF Envelope Following ET Envelope Tracking EVM Error VectorMagnitude FFLPA Feedforward Linear Power Amplifier FIR Finite ImpulseResponse FPGA Field-Programmable Gate Array GSM Global System for Mobilecommunications I-Q In-phase/Quadrature IF Intermediate Frequency LINCLinear Amplification using Nonlinear Components LO Local Oscillator LPFLow Pass Filter MCPA Multi-Carrier Power Amplifier MDS Multi-DirectionalSearch OFDM Orthogonal Frequency Division Multiplexing PA PowerAmplifier PAPR Peak-to-Average Power Ratio PD Digital BasebandPredistortion PLL Phase Locked Loop QAM Quadrature Amplitude ModulationQPSK Quadrature Phase Shift Keying RF Radio Frequency RRH Remote RadioHead RRU Remote Radio Head Unit SAW Surface Acoustic Wave Filter UMTSUniversal Mobile Telecommunications System UPC Up Converter WCDMAWideband Code Division Multiple Access WLAN Wireless Local Area Network

What is claimed is:
 1. A system for data transport in a DistributedAntenna System (DAS), the system comprising: a plurality of remoteDigital Access Units (DAUs) located at a Remote location, wherein eachof the plurality of remote DAUs includes at least one digital opticalinput; a plurality of central hubs, each of the plurality of centralhubs being in communication with one of the remote DAUs using anelectrical communications path; and a plurality of transmit/receivecells, each of the plurality of transmit/receive cells including aplurality of remote hubs, each of the remote hubs in one of theplurality of transmit/receive cells being in communication with one ofthe plurality of central hubs using an optical communications path. 2.The system of claim 1 further comprising a plurality of local DigitalAccess Units (DAUs) located at a Local location, each of the pluralityof local DAUs being operable to receive an RF input from at least one ofa plurality of Base Transceiver Stations (BTSs), each of the pluralityof BTSs having one or more sectors.
 3. The system of claim 2 furthercomprising a local mux/demux coupled to the plurality of local DAUs anda remote mux/demux coupled to the plurality of remote DAUs, wherein thelocal mux/demux and the remote mux/demux are connected via at least oneof Ethernet cable, Optical Fiber, Microwave Line of Sight Link, WirelessLink, or Satellite Link.
 4. The system of claim 3 wherein the localmux/demux and the remote mux/demux comprise at least one of CWDM or DWDMsystems.
 5. The system of claim 3 wherein the remote mux/demux iscoupled to the plurality of remote DAUs by optical cables.
 6. The systemof claim 2 wherein the plurality of local DAUs are connected to theplurality of remote DAUs via at least one CWDM mux/demux and at leastone optical fiber.
 7. The system of claim 1 wherein each of theplurality of central hubs comprises: a transmit path including an RFinput and a plurality of optical outputs; and a receive path including aplurality of optical inputs and an RF output.
 8. The system of claim 1further comprising a server coupled to each of the plurality of centralhubs.
 9. The system of claim 1 wherein the plurality of remote DAUs areoperable to transport digital signals between the plurality of remoteDAUs.
 10. A system for data transport in a Distributed Antenna System,the system comprising: a plurality of remote DAUs located at a Remotelocation, wherein the plurality of remote DAUs are coupled to each otherand operable to transport signals between the plurality of remote DAUs,wherein each of the plurality of remote DAUs includes at least onedigital optical input; a central hub in communication with each of theplurality of remote DAUs using a plurality of electrical communicationspaths; a plurality of transmit/receive cells, each of the plurality oftransmit/receive cells including a plurality of remote hubs, each of theplurality of remote hubs being in communication with the central hubusing one or more optical communications paths.
 11. The system of claim10 further comprising: a plurality of Base Transceiver Stations (BTS),each having one or more sectors; a plurality of BTS RF connections, eachbeing coupled to one of the one or more sectors; and a plurality oflocal Digital Access Units (DAUs) located at a Local location, each ofthe plurality of local DAUs being coupled to each other, operable toroute signals between the plurality of local DAUs, and coupled to atleast one of the plurality of BTS RF connections, wherein the pluralityof local DAUs are in communication with the plurality of remote DAUs.12. The system of claim 11 wherein the plurality of local DAUs arecoupled via at least one of Ethernet cable, Optical Fiber, MicrowaveLine of Sight Link, Wireless Link, or Satellite Link.
 13. The system ofclaim 11 further comprising a local mux/demux coupled to the pluralityof local DAUs and a remote mux/demux coupled to the plurality of remoteDAUs, wherein the local mux/demux and the remote mux/demux are connectedvia at least one of Ethernet cable, Optical Fiber, Microwave Line ofSight Link, Wireless Link, or Satellite Link.
 14. The system of claim 13wherein the local mux/demux and the remote mux/demux comprise at leastone of CWDM or DWDM systems.
 15. The system of claim 13 wherein theremote mux/demux is coupled to the plurality of remote DAUs by opticalcables.
 16. The system of claim 11 wherein the plurality of local DAUsare connected to the plurality of remote DAUs via at least one CWDMmux/demux and at least one optical fiber.
 17. The system of claim 10wherein the central hub comprises: a transmit path including a pluralityof RF inputs and a plurality of optical outputs; and a receive pathincluding a plurality of optical inputs and a plurality of RF outputs.18. The system of claim 10 further comprising a server coupled to thecentral hub.
 19. The system of claim 10 wherein the plurality of remoteDAUs are operable to transport digital signals between the plurality ofremote DAUs.
 20. A method of transporting signals, the methodcomprising: receiving a set of replicated optical signals; providing aset of replicated signals associated with the set of replicated opticalsignals in a remote plane; receiving a first replicated signal at an RFinput of a first central hub; receiving a second replicated signal at anRF input of a second central hub, wherein the second replicated signalis a replication of a different signal than the first replicated signal;transporting a first optical signal associated with the first replicatedsignal to a first remote hub; transporting a second optical signalassociated with the second replicated signal to a second remote hub;broadcasting a first analog signal from the first remote hub; andbroadcasting a second analog signal from the second remote hub.
 21. Themethod of claim 20 wherein the replicated signals comprise analogsignals.
 22. The method of claim 20 wherein providing the set ofreplicated signals comprises transporting the set of replicated signalsusing an RF cable.
 23. The method of claim 20 wherein transporting thefirst optical signal comprises transmitting the first optical signalthough a first optical fiber and transporting the second optical signalcomprises transmitting the second optical signal through a secondoptical fiber.
 24. A method of performing dynamic sectorization, themethod including: providing a set of replicated signals in a remoteplane; receiving the set of replicated signals at RF inputs of a centralhub; switching a first replicated signal from a first RF input to asecond modulator; switching a second replicated signal from a second RFinput to a first modulator; modulating the first replicated signal andthe second replicated signal; converting a signal associated with thefirst replicated signal to a first optical signal; converting a signalassociated with the second replicated signal to a second optical signal;providing the first optical signal at a first optical output of thecentral hub; and providing the second optical signal at a second opticaloutput of the central hub.
 25. The method of claim 24 wherein the firstreplicated signal comprises a first analog signal associated with afirst set of sectors and the second replicated signal comprises a secondanalog signal associated with a second set of sectors.
 26. The method ofclaim 25 wherein the central hub comprises a switching matrix coupled tothe RF inputs of the central hub.
 27. The method of claim 26 wherein theswitching matrix is further coupled to a plurality of sets ofmodulators.